The goal of this Phase I SBIR proposal from Applikate Technologies, LLC, is to validate and optimize RapidView, a novel approach to intraoperative microscopic analysis of excised tissue. Currently, pathologists analyze flash frozen tissue sections to provide immediate histological evaluation of surgical excisions for ~3 million operations per year in the United States. The resulting feedback to the surgeon, which often includes assessment of excised tumor margins, results in alterations to the course of surgery in ~40% of cases. Use of intraoperative frozen sections has been shown to reduce rates of re-operation, with its associated risks and stress for the patient, and decrease total costs to both the provider and insurer. However, artifacts from the freezing process and difficulty freezing certain tissue types limit the use of frozen sections and can lead to critical errors. The resulting distortions in morphology, combined with severe time pressure to provide feedback while the patient is still in surgery, make intraoperative frozen tissue analysis one of the most difficult tasks a pathologist performs. RapidView addresses these problems by providing image quality on par with or better than permanent hematoxylin and eosin stained sections in the same time frame as frozen sections. RapidView uses fresh, unfrozen tissue and thereby avoids cutting and freezing artifacts. The processing for RapidView is also less technically demanding than that of frozen sections and is expected to work with all tissue types. In addition to changing the way intraoperative tissue evaluation is performed, RapidView could change the normal workflow of non-intraoperative pathology by providing images sufficient for primary diagnosis in < 20 minutes, compared with days for conventional approaches that use wax embedded tissue blocks. The specific aims of this proposal are to optimize the RapidView tissue processing protocol for practical implementation and to confirm compatibility with tissue storage and supportive tests sometimes employed following rapid analysis. Successful completion of the aims of this proposal will validate RapidView as a superior alternative to frozen sections and as a potential replacement for wax embedding, setting the stage for Phase II development of specialized hardware for implementing RapidView in a clinical setting.